Article and associated method

ABSTRACT

An article includes a membrane having pores and that is air permeable. A nanoparticle precursor is dispersed throughout the pores, and the nanoparticle precursor is responsive to a stimulus to form a catalytically active nanoparticle. An associated method is also provided.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

This invention was made with Government support under contract numberBAA 05-07 awarded by NATICK under W911-QY-05-C-0102. The Government hascertain rights in the invention.

BACKGROUND

1. Technical Field

The invention includes embodiments relating to catalytically activemembrane. The invention includes embodiments that relate to a method ofmaking and using the catalytically active membrane.

2. Discussion of Related Art

Membranes with high porosity, chemical resistance, and havingcatalytically active particles are useful in high performanceapplications, for example, catalytically-active filters andchemical-biological protective apparels. Protective apparels designedfor use against chemical and biological agents require good comfortproperties in addition to the protective properties.

Expanded PTFE (ePTFE) is desirable for chemical and temperatureresistance, and high air flow for a given pore size. However, due to thehydrophobic property of the ePTFE membrane, it may be difficult toincorporate aqueous dispersions of catalytically active particleshomogeneously into the porous membrane by techniques such asdip-coating, slot-die coating, etc. Non-homogeneous dispersion of theparticles in the pores or on the surface of the membranes lead to poreocclusion resulting in reduced air permeability.

It may be desirable to have a catalytically active membrane withproperties that differ from those properties of currently availablemembranes. It may be desirable to have a catalytically active membraneproduced by a method that differs from those methods currentlyavailable.

BRIEF DESCRIPTION

In one embodiment, an article is provided. An article includes amembrane having pores and that is air permeable. A nanoparticleprecursor is dispersed throughout the pores, and the nanoparticleprecursor is responsive to a stimulus to form a catalytically activenanoparticle.

In one embodiment, an article includes a membrane having pores and thatis air permeable. A plurality of nanoparticles is dispersed throughoutthe pores, and the nanoparticles are catalytically active.

In one embodiment, a method is provided. The method includes exposing achembio agent to a membrane having pores and having a plurality ofcatalytically active nanoparticles dispersed throughout the pores. Themethod further includes infiltrating the chembio agent into the poresand reacting the chembio agent with the nanoparticles within the pores.

BRIEF DESCRIPTION OF DRAWING FIGURES

FIG. 1 shows a cross-section of an article in accordance with oneembodiment of the invention.

FIG. 2 shows a cross-section of an article in accordance with oneembodiment of the invention.

FIG. 3 shows a cross-section of an article in accordance with oneembodiment of the invention.

FIG. 4 shows a cross-section of an article in accordance with oneembodiment of the invention.

FIG. 5 shows a cross-section of an article in accordance with oneembodiment of the invention.

FIG. 6 shows a cross-section of a filter in accordance with oneembodiment of the invention.

FIG. 7 shows a cross-section of a filter in accordance with oneembodiment of the invention.

FIG. 8 shows a cross-section of a filter in accordance with oneembodiment of the invention.

FIG. 9 shows a cross-section of a filter in accordance with oneembodiment of the invention.

FIG. 10 shows a scanning electron micrograph of a catalytically activenanoparticle loaded membrane.

DETAILED DESCRIPTION

The invention includes embodiments that relate to a catalytically activearticle. The invention includes embodiments that relate to methods ofmaking and using the catalytically active article.

In the following specification and the clauses which follow, referencewill be made to a number of terms have the following meanings. Thesingular forms “a”, “an” and “the” include plural referents unless thecontext clearly dictates otherwise. Approximating language, as usedherein throughout the specification and clauses, may be applied tomodify any quantitative representation that could permissibly varywithout resulting in a change in the basic function to which it isrelated. Accordingly, a value modified by a term such as “about” is notto be limited to the precise value specified. In some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value. Similarly, “free” may be used in combinationwith a term, and may include an insubstantial number, or trace amounts,while still being considered free of the modified term.

As used herein, the terms “may” and “may be” indicate a possibility ofan occurrence within a set of circumstances; a possession of a specifiedproperty, characteristic or function; and/or qualify another verb byexpressing one or more of an ability, capability, or possibilityassociated with the qualified verb. Accordingly, usage of “may” and “maybe” indicates that a modified term is apparently appropriate, capable,or suitable for an indicated capacity, function, or usage, while takinginto account that in some circumstances the modified term may sometimesnot be appropriate, capable, or suitable. For example, in somecircumstances an event or capacity can be expected, while in othercircumstances the event or capacity cannot occur—this distinction iscaptured by the terms “may” and “may be”.

In one embodiment, an article is provided. The article includes amembrane having pores and that is air permeable. A nanoparticleprecursor is dispersed throughout the pores, and the nanoparticleprecursor is responsive to a stimulus to form a catalytically activenanoparticle. As used herein the term “air permeable” means that themembrane has contiguous air pathways from one side of the membrane tothe other side of the membrane. As used herein, an air permeablemembrane has an air permeability that is greater than about 0.01 cfm/ft²at 0.5 inches H₂O measured using the ASTM D737 method.

In one embodiment, the membrane may include a fluorinated polymer. Asused herein, the term “fluorinated polymer” refers to a polymer in whichsome or all of the hydrogen atoms are replaced by fluorine. In oneembodiment, the membrane may include a fluorinated polyolefin. As usedherein, the term “fluorinated polyolefin” refers to a fluorinatedpolymer derived from one or more fluorinated polymer precursorscontaining ethylenic unsaturation. A suitable fluorinated polymerprecursor may be a partially fluorinated olefin which may include othersubstituents, e.g. chlorine or hydrogen. A suitable fluorinated polymerprecursor may be a straight or branched chain compound having a terminalethylenic double bond. In one embodiment, a suitable polymer precursormay include one or more of hexafluoropropylene, pentafluoropropylene,tetrafluoroethylene, vinylidine fluoride, or perfluoroalkyl vinylethers, for example, perfluoro (methyl vinyl ether) or (propyl vinylether).

In one embodiment, a fluorinated polyolefin essentially includes or bothof polyvinylidene fluoride or polytetrafluoroethylene. In oneembodiment, a fluorinated polyolefin essentially includes expandedpolytetrafluoroethylene (ePTFE). Suitable ePTFE membranes may becommercially obtainable from General Electric Energy (Kansas City, Mo.).

In some embodiments, a suitable membrane includes one or more ofpolyalkene, polyarylene, polyamide, polyester, polysulfone, polyether,polyacrylic, polystyrene, polyurethane, polyarylate, polyimide,polycarbonate, polysiloxane, polyphenylene oxide, cellulosic polymer, orsubstituted derivatives thereof. In some embodiments, the membraneincludes a biocompatible material or a biodegradable material, such asaliphatic polyesters, polypeptides and other naturally occurringpolymers.

In one embodiment, the membrane may be made by extruding a mixture offine powder particles and lubricant. The extrudate subsequently may becalendered. The calendered extrudate may be “expanded” or stretched inone or more directions, to form fibrils connecting nodes to define athree-dimensional matrix or lattice type of structure. “Expanded” meansstretched beyond the elastic limit of the material to introducepermanent set or elongation to fibrils. The membrane may be heated or“sintered” to reduce and minimize residual stress in the membranematerial by changing portions of the material from a crystalline stateto an amorphous state. In one embodiment, the membrane may be unsinteredor partially sintered as is appropriate for the contemplated end use ofthe membrane. In one embodiment, the membrane may define manyinterconnected pores that fluidly communicate with environments adjacentto the opposite facing major sides of the membrane.

Other materials and methods may be used to form the membrane having anopen pore structure. The membrane may be rendered permeable by, forexample, one or more of perforating, stretching, expanding, bubbling,precipitating or extracting the base membrane. Suitable methods ofmaking the membrane include foaming, skiving or casting any of thesuitable materials. In alternate embodiments, the membrane may be formedfrom woven or non-woven fibers.

In one embodiment, continuous pores may be produced. Suitable porositymay be in a range of greater than about 10 percent by volume. In oneembodiment, the porosity may be in a range of from about 10 percent toabout 20 percent, from about 20 percent to about 30 percent, from about30 percent to about 40 percent, from about 40 percent to about 50percent, from about 50 percent to about 60 percent, from about 60percent to about 70 percent, from about 70 percent to about 80 percent,from about 80 percent to about 90 percent, or greater than about 90percent by volume. Here and throughout the specification and claims,range limitations may be combined and/or interchanged. Such ranges areidentified by their range limitations, and include all the sub-rangescontained therein unless context or language indicates otherwise.

Pore diameter may be uniform from pore to pore, and the pores may definea predetermined pattern. Alternatively, the pore diameter may differfrom pore to pore, and the pores may define an irregular pattern.Suitable pore diameters may be less than about 500 micrometers. In oneembodiment, an average pore diameter may be in a range of from about 1micrometer to about 10 micrometers, from about 10 micrometers to about50 micrometers, from about 50 micrometers to about 100 micrometers, fromabout 100 micrometers to about 250 micrometers, or from about 250micrometers to about 500 micrometers. In one embodiment, the averagepore diameter may be less than about 1 micrometer, in a range of fromabout 1 nanometer to about 50 nanometers, from about 50 nanometers toabout 0.1 micrometers, from about 0.1 micrometers to about 0.5micrometers, or from about 0.5 micrometers to about 1 micrometer. In oneembodiment, the average pore diameter may be less than about 1nanometer. In one embodiment, the pores may essentially have an averagepore diameter in a range of from about 10 nanometers to about 10micrometers.

Surfaces of nodes and fibrils may define numerous interconnecting poresthat extend through the membrane between opposite major side surfaces ina tortuous path. In one embodiment, the average effective pore size ofpores in the membrane may be in the micrometer range. In one embodiment,the average effective pore size of pores in the membrane may be in thenanometer range. A suitable average effective pore size for pores in themembrane may be in a range of from about 0.01 micrometers to about 0.1micrometers, from about 0.1 micrometers to about 5 micrometers, fromabout 5 micrometers to about 10 micrometers, or greater than about 10micrometers.

In one embodiment, the membrane may be a three-dimensional matrix orhave a lattice type structure including plurality of nodesinterconnected by a plurality of fibrils. Surfaces of the nodes andfibrils may define a plurality of pores in the membrane. The size of afibril may be in a range of from about 0.05 micrometers to about 0.5micrometers in diameter taken in a direction normal to the longitudinalextent of the fibril. The specific surface area of the membrane may bein a range of from about 9 square meters per gram of membrane materialto about 110 square meters per gram of membrane material.

Membranes according to embodiments of the invention may have differingdimensions, some selected with reference to application-specificcriteria. In one embodiment, the membrane may have a thickness in thedirection of fluid flow in a range of less than about 10 micrometers. Inanother embodiment, the membrane may have a thickness in the directionof fluid flow in a range of greater than about 10 micrometers, forexample, in a range of from about 10 micrometers to about 100micrometers, from about 100 micrometers to about 1 millimeter, fromabout 1 millimeter to about 5 millimeters, or greater than about 5millimeters. In one embodiment, the membrane may have an averagethickness in a range of from about 0.0005 inches (12.7 micrometers) toabout 0.005 inches (127 micrometers). In one embodiment, the membranemay be formed from a plurality of differing layers.

Perpendicular to the direction of fluid flow, the membrane may have awidth of greater than about 10 millimeters. In one embodiment, themembrane may have a width in a range of from about 10 millimeters toabout 45 millimeters, from about 45 millimeters to about 50 millimeters,from about 50 millimeters to about 10 centimeters, from about 10centimeters to about 100 centimeters, from about 100 centimeters toabout 500 centimeters, from about 500 centimeters to about 1 meter, orgreater than about 1 meter. The width may be a diameter of a circulararea, or may be the distance to the nearest peripheral edge of apolygonal area. In one embodiment, the membrane may be rectangular,having a width in the meter range and an indeterminate length. That is,the membrane may be formed into a roll with the length determined bycutting the membrane at predetermined distances during a continuousformation operation.

In one embodiment, the membrane may have a unit average weight in arange of less than about 0.05 oz/yd². In one embodiment, the membranemay have a unit average weight in a range of from about 0.05 oz/yd² toabout 0.1 oz/yd², from about 0.1 oz/yd² to about 0.5 oz/yd², from about0.5 oz/yd² to about 1 oz/yd², from about 1 oz/yd² to about 2 oz/yd², orfrom about 2 oz/yd² to about 3 oz/yd².

A nanoparticle precursor may be dispersed throughout the pores of themembrane. A nanoparticle precursor may refer to a compound capable ofbeing converted to a catalytically active nanoparticle when exposed to astimulus. In one embodiment, a nanoparticle precursor may include one ormore metal and a ligand.

In one embodiment, a metal in the nanoparticle precursor may include oneor more silver of (Ag), copper (Cu), zinc (Zn), aluminum (Al), magnesium(Mg), or titanium (Ti).

A suitable ligand may include a molecule or an ion having at least oneatom having a lone pair of electrons that may bond to a metal atom orion. A ligand may also include unsaturated molecules or ions that maybind to a metal atom or ion. Unsaturated molecules or ions may includeat least one carbon-carbon double bond formed by the side-by-sideoverlap of p-atomic orbitals on adjacent atoms. In one embodiment, theligand may include an alkoxide group or a carbamate group.

A ligand may further include an organic backbone or an inorganicbackbone. An organic backbone for the ligand may have only carbon-carbonlinkages (for example, olefins) or carbon-heteroatom-carbon linkages(for example, ethers, esters and the like) in the main chain. Aninorganic backbone for a ligand may include main chain linkages otherthan that of carbon-carbon linkages or carbon-heteroatom-carbonlinkages, for example, silicon-silicon linkages in silanes,silicon-oxygen-silicon linkages in siloxanes,phosphorous-nitrogen-phosphorous linkages in phosphazenes, and the like.

In one embodiment, a nanoparticle precursor may include one or more of ametal alkoxide, a metal halide, or a metal carbamate. A suitablealkoxide may include a metal ethoxide, a metal isopropoxide, or a metalbutoxide. In one embodiment, a nanoparticle precursor may essentiallyinclude titanium alkoxide. In one embodiment, a nanoparticle precursormay essentially include silver carbamate.

In one embodiment, a nanoparticle precursor may decompose when exposedto a stimulus to form elemental metal, a metal oxide, or a mixed metaloxide. Elemental metal refers to a substantially pure metal or alloyhaving an oxidation state of zero. In one embodiment, a nanoparticleprecursor may decompose when exposed to a stimulus to form a titaniumoxide (TiO₂) nanoparticle. In one embodiment, a nanoparticle precursormay decompose when exposed to a stimulus to form a silver nanoparticle.

The amount of nanoparticle precursor in the membrane may vary depend onone or more of: the end-use, relative amount of metal in the entirenanoparticle precursor, amount of nanoparticle required in the finalcomposition, and other factors. In one embodiment, the membrane mayinclude a nanoparticle precursor in an amount that is less than about0.1 weight percent. In one embodiment, the membrane may include ananoparticle precursor in an amount in a range of from about 0.1 weightpercent to about 1 weight percent, from about 1 weight percent to about2 weight percent, from about 2 weight percent to about 5 weight percent,from about 5 weight percent to about 10 weight percent of the membrane.In one embodiment, the membrane may include a nanoparticle precursor inan amount in a range of from about 10 weight percent to about 20 weightpercent, from about 20 weight percent to about 30 weight percent, fromabout 30 weight percent to about 40 weight percent, or from about 40weight percent to about 50 weight percent of the membrane. In oneembodiment, the membrane may include a nanoparticle precursor in anamount that is greater than about 50 weight percent.

A nanoparticle precursor, as described hereinabove may decompose whenexposed to a stimulus to form a catalytically active nanoparticle. Inone embodiment, the nanoparticle precursor may decompose when exposed toa stimulus selected from the group consisting of electromagneticradiation, thermal energy, or water. Electromagnetic radiation mayinclude ultraviolet, infrared, visible, electron beam, or microwaveradiation. Electromagnetic radiation may include a coherent beam, forexample, in a laser.

Thermal energy may include application of heat to the nanoparticleprecursor resulting in an increase in temperature of the membrane. Inone embodiment, the nanoparticle precursor may decompose by heating thenanoparticle precursor to a temperature in a range of from about roomtemperature (RT) to about 40 degrees Celsius, from about 40 degreesCelsius to about 60 degrees Celsius, from about 60 degrees Celsius toabout 80 degrees Celsius, from about 80 degrees Celsius to about 100degrees Celsius, from about 100 degrees Celsius to about 120 degreesCelsius, or from about 120 degrees Celsius to about 150 degrees Celsius.In one embodiment, the nanoparticle precursor may decompose by heatingthe nanoparticle precursor to a temperature in a range of from about 150degrees Celsius to about 175 degrees Celsius to, from about 175 degreesCelsius to about 200 degrees Celsius, from about 200 degrees Celsius toabout 225 degrees Celsius, or from about 225 degrees Celsius to about250 degrees Celsius. In one embodiment, the nanoparticle precursor maydecompose essentially at a temperature in a range of less than about 120degrees Celsius.

Decomposition by exposure to water may include exposing the nanoparticleprecursor in the membrane to a water or water vapor source. In oneembodiment, the stimulus may include exposing the nanoparticle precursorto air, wherein the nanoparticle precursor may be hydrolyzed by themoisture in the air to form the catalytically active nanoparticles.

In some embodiments, the stimulus may include a reducing agent. Areducing agent may refer to a compound capable of reducing the metalcompound in the nanoparticle precursor to its elemental form or to forma metal oxide. In one embodiment, the reducing agent may be selectedfrom the group consisting of alcohols, aldehydes, amines, amides,alanes, boranes, borohydrides, aluminohydrides, onium salts, andorganosilanes. In one embodiment, the reducing agent essentiallyincludes one or more of onium salt, alcohol, amine, amide, borane,borohydride, or organosilane. In one embodiment, the reducing agentessentially includes an onium salt. In one embodiment, the reducingagent essentially includes an iodonium salt. In one embodiment, thestimulus may include application of thermal energy and contact with areducing agent. In one embodiment, the stimulus may include exposure towater.

The amount of reducing agent may depend on the reaction conditions andon the selected nanoparticle precursor. In one embodiment, the reducingagent may be present in an amount equal to or greater than the minimumstoichiometric amount necessary to convert all of the metal in thenanoparticle precursor to its elemental form or to form a metal oxide atthe desired conversion conditions. In one embodiment, an amount ofreducing agent employed may be in excess relative to the amount of thenanoparticle precursor.

In one embodiment, an article may include a decomposition product of thenanoparticle precursor. A decomposition product of the nanoparticleprecursor may include a catalytically active nanoparticle.“Catalytically active nanoparticles”', as used herein, include particleswith active species or particles capable of generating active species inresponse to a stimulus (for example, UV radiation). The active speciesmay be capable of reacting or interacting with chembio agents or fluidcontaminants to reduce their activity, to increase their infiltrationtime through the membrane, or convert them to a harmless by-product orend-product.

Nanoparticle as used herein refers to particles having an averageparticle size on the nano scale. A nanoparticle may have a largestdimension (for example, a diameter or length) in the range of from about1 nanometer to 1000 nanometers. Nanoparticle as used herein, may referto a single nanoparticle, a plurality of nanoparticles, or a pluralityof nanoparticles associated with each other. Associated refers to ametal nanoparticle in contact with at least one other metalnanoparticle. In one embodiment, associated refers to a metalnanoparticle in contact with more than one other particle.

In one embodiment, a decomposition product of the nanoparticle precursormay include a catalytically active metal nanoparticle. In oneembodiment, the decomposition reaction may not go to completion, and themembrane may include unreacted nanoparticle precursor in addition to thedecomposition product. In one embodiment, the membrane may includeunreacted nanoparticle precursor and metal nanoparticle. In oneembodiment, the membrane may include unreacted nanoparticle precursor,metal nanoparticle, and a decomposition product of the ligand. Forexample, in one embodiment, a decomposition product of a metal carbamatenanoparticle precursor may include unreacted nanoparticle precursor,metal nanoparticle, an amine, and carbon dioxide. Similarly, in oneembodiment, a decomposition product of a metal alkoxide nanoparticleprecursor may include unreacted nanoparticle precursor, metalnanoparticle, and an alkane.

In one embodiment, all the metal in the nanoparticle precursor may notbe converted to a catalytically active metal nanoparticle. In oneembodiment, greater than about 90 weight percent of the metal in thenanoparticle precursor may be converted to a catalytically activenanoparticle. In one embodiment, a weight percent of the metal in thenanoparticle precursor that may be converted to a catalytically activenanoparticle may be in a range of from about 25 percent to about 40weight percent, from about 40 weight percent to about 60 weight percent,from about 60 weight percent to about 75 weight percent, or from about75 weight percent to about 90 weight percent. In one embodiment, greaterthan about 25 weight percent of the metal in the nanoparticle precursormay be converted to a catalytically active nanoparticle.

In one embodiment, a catalytically active nanoparticle may includetitanium dioxide. In one embodiment, a catalytically active nanoparticlemay include elemental silver. In one embodiment, a catalytically activenanoparticle may include an oxide of aluminum, silver, copper, ormagnesium.

As described herein earlier, a nanoparticle may refer to a singleparticle or may include a plurality of particles. The plurality ofparticles may be characterized by one or more of average particle size,particle size distribution, average particle surface area, particleshape, or particle cross-sectional geometry.

The size of the nanoparticle may depend on the pore size of the membraneused and on the activity to size relationship of the active nanoparticleused. In one embodiment, an average particle size of the nanoparticlemay be in a range of less than about 1 nanometer. In one embodiment, anaverage particle size of the nanoparticle may be in a range of fromabout 1 nanometer to about 10 nanometers, from about 10 nanometers toabout 25 nanometers, from about 25 nanometers to about 50 nanometers,from about 50 nanometers to about 75 nanometers, or from about 75nanometers to about 100 nanometers. In one embodiment, an averageparticle size of the nanoparticle may be in a range of from about 100nanometers to about 200 nanometers, from about 200 nanometers to about300 nanometers, from about 300 nanometers to about 400 nanometers, orfrom about 400 nanometers to about 500 nanometers. In one embodiment, anaverage particle size of the nanoparticle may be essentially in a rangeof from about 5 nanometers to about 500 nanometers.

A plurality of particles may have a distribution of particle sizes thatmay be characterized by both a number-average size and a weight-averageparticle size. The number-average particle size may be represented byS_(N)=Σ(s_(i)n_(i))Σn_(i), where n_(i) is the number of particles havinga particle size s_(i). The weight average particle size may berepresented by S_(W)=Σ(s_(i)n_(i) ²)Σ(s_(i)n_(i)). When all particleshave the same size, S_(N) and S_(W) may be equal. In one embodiment,there may be a distribution of sizes, and S_(N) may be different fromS_(W). The ratio of the weight average to the number average may bedefined as the polydispersity index (S_(PDI)). In one embodiment,S_(PDI) may be equal to about 1. In one embodiment, S_(PDI) may be in arange of from about 1 to about 1.2, from about 1.2 to about 1.4, fromabout 1.4 to about 1.6, or from about 1.6 to about 2.0. In oneembodiment, S_(PDI) may be in a range that is greater than about 2.0.

In one embodiment, the metal nanoparticle may include a plurality ofparticles having a particle size distribution selected from the groupconsisting of normal distribution, unimodal distribution, and bimodaldistribution. Certain particle size distributions may be useful toprovide certain benefits, and other ranges of particle sizedistributions may be useful to provide other benefits. A normaldistribution may refer to a distribution of particle sizes with S_(PDI)equal to 1. A unimodal distribution may refer to a distribution ofparticle sizes having the same particle size. In another embodiment,nanoparticle particles having two distinct size ranges (a bimodaldistribution) may be included in the membrane: the first range fromabout 1 nanometer to about 10 nanometers, and the second range fromabout 20 nanometers to about 50 nanometers. In another embodiment, amembrane may essentially include a unimodal distribution of nanoparticlesizes.

A nanoparticle may have a variety of shapes and cross-sectionalgeometries. In one embodiment, a nanoparticle may have a shape that is asphere, a rod, a tube, a flake, a fiber, a plate, a wire, a cube, or awhisker. A nanoparticle may include particles having two or more of theaforementioned shapes. In one embodiment, a cross-sectional geometry ofthe particle may be one or more of circular, ellipsoidal, triangular,rectangular, or polygonal. In one embodiment, a nanoparticle may consistessentially of non-spherical particles. For example, such particles mayhave the form of ellipsoids, which may have all three principal axes ofdiffering lengths, or may be oblate or prelate ellipsoids of revolution.Non-spherical nanoparticles may alternatively be laminar in form,wherein laminar refers to particles in which the maximum dimension alongone axis is substantially less than the maximum dimension along each ofthe other two axes. Non-spherical nanoparticles may also have the shapeof frusta of pyramids or cones, or of elongated rods. In one embodiment,the nanoparticles may be irregular in shape. In one embodiment, thenanoparticle may consist essentially of spherical particles.

A nanoparticle may have a high surface-to-volume ratio. A nanoparticlemay be crystalline or amorphous. In one embodiment, a single type (size,shape, and the like) of nanoparticle may be used, or mixtures ofdifferent types of nanoparticles may be used. If a mixture ofnanoparticles is used they may be homogeneously distributed in the poresof the membrane.

In one embodiment, an article may include a membrane having pores andthat is air permeable. A plurality of nanoparticles is dispersedthroughout the pores, and the nanoparticles are catalytically active. Inone embodiment, the nanoparticles may be dispersed uniformly throughoutthe pores of the membrane.

In one embodiment, the catalytically active nanoparticle may be presentin an effective amount. An effective amount of nanoparticle refers toamount of nanoparticle required to provide the catalytically activespecies sufficient to meet the performance requirements of the end-useapplication. In one embodiment, the membrane may include a nanoparticlein an amount that is less than about 0.1 weight percent of the combinedweight of the membrane and the nanoparticle. In one embodiment, themembrane may include a nanoparticle in an amount in a range of fromabout 0.1 weight percent to about 1 weight percent, from about 1 weightpercent to about 2 weight percent, from about 2 weight percent to about5 weight percent, from about 5 weight percent to about 10 weight percentof the combined weight of the membrane and the nanoparticle. In oneembodiment, the membrane may include a nanoparticle in an amount in arange of from about 10 weight percent to about 20 weight percent, fromabout 20 weight percent to about 30 weight percent, from about 30 weightpercent to about 40 weight percent, or from about 40 weight percent toabout 50 weight percent of the combined weight of the membrane and thenanoparticle. In one embodiment, the membrane may include a metalnanoparticle in an amount that is greater than about 50 weight percentof the combined weight of the membrane and the nanoparticle. In oneembodiment, the nanoparticle is present in an amount in a range of fromabout 0.1 weight percent to about 20 weight percent of the combinedweight of the membrane and the nanoparticle.

In one embodiment, a catalytically active nanoparticle may be capable ofreacting or interacting with a chembio agent to inactivate the chembioagent. As used herein the term “inactivating a chembio agent” mayinclude one or both of reducing the biological activity of the chembioagent or increasing an amount of time for a significant amount ofunreacted biologically active chembio agent to pass through the article.As used herein, the term “chembio agent” includes a chemical agent, abiological agent, or combinations of chemical agent and biologicalagent. A chemical agent may be a non-living chemical substance havingtoxic properties. A chemical agent may include nonliving toxic productsproduced by living organisms e.g., toxins. A biological agent may be aliving or a quasi-living material (e.g., prions) having toxicproperties.

In one embodiment, a chembio agent may include a chemical warfare agent.Suitable chemical warfare agents may include one or more incapacitatingagents, lachrymators, vesicants or blister agents, nerve agents,pulmonary agents, blood agents, or malodorants.

Suitable incapacitating agents may include nervous system affecters,vomiting agents, choking agents, hallucinogens, sedatives, narcotics,depressants, and the like, and combinations of two or more thereof. Inone embodiment, an incapacitating agent may include 3-quinuclidinylbenzilate (QNB, BZ), which may be an anticholinergic agent that mayreact with a probe comprising, for example, choline. Alternative nervoussystem affecters may include commercially available over the counter(OTC) or prescription pharmaceutical compositions. In one embodiment, anincapacitating agent may include curare, or a curare analog orderivative.

Suitable lachrymators may include one or more ofo-chlorobenzylmalonitrile, chloromethyl chloroformate, stannic chloride,sym-dichloromethyl ether, benzyl bromide, xylyl bromide, methylchlorosulphonate, ethyl iodoacetate, bromacetone, bromomethyl-ethylketone, acrolein (2-propanal), capsaicin including analogs andderivatives, or the like.

A suitable vesicant may include one or more of sulfur mustard, nitrogenmustard, or an arsenical such as Lewisite. Suitable sulfur mustard mayinclude one or more of 2-chloroethyl chloromethyl sulfide,bis(2-chloroethyl) sulfide or dichloroethyl disulfide, bis(2-chloroethylthio) methane, 1,2-bis (2-chloroethylthio) ethane, 1,3-bis(2-chloroethylthio)-n-propane, 1,4-bis (2-chloroethylthio)-n-butane,1,5-bis (2-chloroethylthio)-n-pentane, bis (2-chloroethylthiomethyl)ether, or bis (2-chloroethyl thioethyl) ether. Suitable nitrogen mustardmay include one or more of bis (2-chloroethyl) ethylamine, bis(2-chloroethyl) methylamine, or tris (2-chloroethyl) amine. SuitableLewisites may include one or more of 2-chlorovinyl dichloroarsine, orbis (2-chlorovinyl) chloroarsine, tris (2-chlorovinyl) arsine.

Suitable nerve agents may include cholinesterase inhibitors. In oneembodiment, a cholinesterase inhibitor may include one or more ofo-alkyl (Me, Et, n-Pr or i-Pr)—phosphonofluoridates, such as o-isopropylmethylphosphonofluoridate (sarin) or o-pinacolylmethylphosphonofluoridate (soman); o-alkyl N,N-dialkyl (Me, Et, n-Pr ori-Pr) phosphoramidocyanidates, such as o-ethyl N,N-dimethylphosphoramidocyanidate (tabun); or o-alkyl S-2-dialkyl (Me, Et, n-Pr ori-Pr)-aminoethyl alkyl (Me, Et, n-Pr or i-Pr) phosphonothiolates andcorresponding alkylated or protonated salts, such as o-ethylS-2-diisopropylaminoethyl methyl phosphonothiolate.

Suitable pulmonary agents may include one or both of phosgene (carbonylchloride) and perfluroroisobutylene. Suitable chemical toxins mayinclude one or more of palytoxin, ricin, saxitoxin, or botulinum toxin.

Suitable blood agents may include forms of cyanide such as salts, andanalogs and derivatives of cyanide salts. A suitable solid salt ofcyanide may include sodium, potassium, and/or calcium. A suitablevolatile liquid form of cyanide may include hydrogen cyanide and/orcyanogen chloride.

In one embodiment, a chembio agent may include one or more biologicalagents. Suitable biological agents may include pathogens. Pathogens areinfectious agents that may cause disease or illness to their host(animal or plant). Biological agents may include prions, microorganisms(viruses, bacteria and fungi) and some unicellular and multicellulareukaryotes (for example parasites) and their associated toxins. In someembodiments, pathogens may include one or more of bacteria, protozoa,fungus, parasites, or spore. In some embodiments, pathogens may includevirus or prion.

Some examples of bacterial biological agents (and the diseases or effectcaused by them) may include one or more of: escherichia coli(peritonitis, food poisoning); mycobacterium tuberculosis(tuberculosis); bacillus anthracis (anthrax); salmonella (foodpoisoning); staphylococcus aureus (toxic shock syndrome); streptococcuspneumoniae (pneumonia); streptococcus pyogenes (strep throat);helicobacter pylori (stomach ulcers); or francisella tularensis(tularemia).

Some examples of viruses (and the diseases or effect caused by them) mayinclude one or more of hepatitis A, B, C, D and E (liver disease);influenza virus (flu, Avian flu); SARS coronavirus (severe acuterespiratory syndrome); herpes simplex virus (herpes); molluscumcontagiosum (rash); or human immunodeficiency virus (AIDS).

Some examples of protozoa (and the diseases or effect caused by them)may include one or more of cryptosporidium (cryptosporidiosis); giardialamblia (giardiasis); plasmodium (malaria); or trypanosoma cruzi (chagasdisease). Some examples of fungi (and the diseases or effect caused bythem) may include one or more of pneumocystis jiroveci (opportunisticpneumonia); tinea (ringworm); or candida (candidiasis).

Some examples of parasites may include one or more of roundworm,scabies, tapeworm, or flatworm. Some examples of protein-based pathogensmay include prions (Bovine spongiform encephalopathy (BSE) commonlyknown as mad cow disease or variant Creutzfeldt-Jakob disease (vCJD)).

Toxins include proteins capable of causing disease on contact orabsorption with body tissues by interacting with biologicalmacromolecules and may be used as bioweapons. Suitable toxins mayinclude Ricin, SEB, Botulism toxin, Saxitoxin, and many Mycotoxins.

Some other examples of diseases caused by biological agents may includeanthrax, Ebola, Bubonic Plague, Cholera, Tularemia, Brucellosis, Qfever, Machupo, Coccidioides mycosis, Glanders, Melioidosis, Shigella,Rocky Mountain Spotted Fever, Typhus, Psittacosis, Yellow Fever,Japanese B Encephalitis, Rift Valley Fever, or Smallpox.

In one embodiment, a catalytically active nanoparticle may be capable ofreacting or interacting with a contaminant in a fluid stream to form areaction product having properties different from that of thecontaminant in the fluid stream. In one embodiment, the contaminants inthe fluid may react or interact with the catalytically activenanoparticle to form a more desirable by-product or end product, andtherefore remove the contaminants from the fluid stream. As used herein,the term “fluid” may include any form of readily flowing material,including liquids and gases.

A contaminant may include air pollutants or water pollutants. Airpollutants may include one or more of nitrogen monoxide, nitrogendioxide, ammonia, carbon monoxide, carbon dioxide, sulfur dioxide,hydrogen cyanide, mercury, dioxin, furan, or volatile organics. Waterpollutants may include one or more of volatile organic chlorinecompounds such as trichloroethene and tetrachloroethene used in largeamounts as degreasing agents and cleaning agents in various industrialfields.

In one embodiment, a catalytically active nanoparticle may be capable ofinteracting with a contaminant in a gaseous stream, for example, airpollutants. In one embodiment, a catalytically active nanoparticle maybe capable of interacting with NO, NO₂, or NH₃ to form nitrogen andwater. In one embodiment, a catalytically active nanoparticle may becapable on interacting with CO to form CO₂. In one embodiment, acatalytically active nanoparticle may be capable of interacting withdioxin or furan to form CO₂ or HCl. In one embodiment, a catalyticallyactive nanoparticle may be capable of interacting with ozone to form O₂.

A membrane may be characterized by one or more of air permeability,moisture vapor transmission rate (MVTR), or chembio agent permeability.In one embodiment, the membrane may have air permeability that isgreater than about 0.01 cfm/ft² at 0.5 inches H₂O. In one embodiment,the membrane may have air permeability that is in a range of from about0.01 cfm/ft² to about 0.02 cfm/ft², from about 0.02 cfm/ft² to about0.03 cfm/ft², from about 0.03 cfm/ft² to about 0.04 cfm/ft², from about0.04 cfm/ft² to about 0.05 cfm/ft² at 0.5 inches H₂O, or from about 0.04cfm/ft² to about 0.05 cfm/ft². In one embodiment, the membrane may haveair permeability that is greater than about 1 cfm/ft² at 0.5 inches H₂O.Air permeability as described herein maybe measured using the testconditions described herein in the specification.

In one embodiment, the membrane may have permeability to a chembio agentthat is less than about 20 micrograms/24 hours. In one embodiment, themembrane may have a permeability to a chembio agent in a range of fromabout 1 microgram/24 hours to about 2 micrograms/24 hours, from about 2microgram/24 hours to about 5 micrograms/24 hours, from about 5microgram/24 hours to about 10 micrograms/24 hours, from about 10microgram/24 hours to about 15 micrograms/24 hours, or from about 15microgram/24 hours to about 20 micrograms/24 hours. In one embodiment,the membrane may have a permeability to a chembio agent that is lessthan about 1 microgram/24 hours.

In one embodiment, the membrane may have a moisture vapor transmissionrate (MVTR) that is greater than about 500 g/m²/day. In one embodiment,the membrane may have a moisture vapor transmission rate in a range offrom about 500 g/m²/day to about 600 g/m²/day, from about 600 g/m²/dayto about 800 g/m²/day, from about 800 g/m²/day to about 1000 g/m²/day,from about 1000 g/m²/day to about 1500 g/m²/day, or from about 1500g/m²/day to about 2000 g/m²/day. In one embodiment, the membrane mayhave a moisture vapor transmission rate (MVTR) that is greater thanabout 2000 g/m²/day.

In one embodiment, the article may have a moisture vapor transmissionrate (MVTR) that is greater than about 4000 g/m²/day. In one embodiment,the article may have a moisture vapor transmission rate in a range offrom about 4000 g/m²/day to about 5000 g/m²/day, from about 5000g/m²/day to about 6000 g/m²/day, from about 6000 g/m²/day to about 7000g/m²/day, from about 7000 g/m²/day to about 8000 g/m²/day, or from about8000 g/m²/day to about 10000 g/m²/day. In one embodiment, the articlemay have a moisture vapor transmission rate (MVTR) that is greater thanabout 10000 g/m²/day.

In one embodiment, a laminate is provided. A laminate may include thecatalytically active membrane described hereinabove and at least oneadditional layer such as a membrane, film or fabric. In one embodiment,catalytically active membrane 12 may be supported on one or more fabriclayer 14 as shown in FIG. 1 to form a laminate 10. In one embodiment, afabric layer may be sufficiently flexible, pliable and durable for usein articles of apparel or enclosures such as garments, tents, sleepingbags, casualty bags, and the like.

In one embodiment, one or more fabric layer may include a polymerselected from poly(aliphatic amide), poly(aromatic amide), polyester,polyolefin, wool, cellulose based fibers such as cotton, rayon, linen,cellulose acetate and other modified cellulose, polyurethane, acrylics,modacrylics, or a blend comprising any of the above. In one embodiment,one or more fabric layer may include cotton, poly (aliphatic amide),poly (aromatic amide), polyester, polyurethanes, or blends thereof.

In some embodiments, one or more fabric layer may be made of wovenfabric. In alternate embodiments, one or more fabric layer may be madeof a non-woven fabric. A non-woven fabric may be knit, braided, tufted,or felted.

In one embodiment, a laminate may include a catalytically activemembrane and at least two fabric materials. The two fabric layers mayinclude the same fabric material or may include different fabric layers.In one embodiment, a laminate 20 may include an outer fabric layer 24and an inner fabric layer 26 as shown in FIG. 2. The catalyticallyactive membrane 22 may be sandwiched between the outer fabric layer 22and the inner fabric layer 26. In one embodiment, a catalytically activemembrane 32 may be supported on an inner fabric layer 34. The innerfabric layer 34 may be supported on an outer fabric layer 36 to form alaminate 30 as shown in FIG. 3.

An outer fabric layer is the outermost layer of the laminate, which isexposed to the elements. In one embodiment, an outer fabric layer may bewoven fabric made of poly(aliphatic amide), poly (aromatic amide),polyester, acrylic, cotton, wool and the like. In one embodiment, theouter fabric layer may be treated to render it hydrophobic oroleophobic. In one embodiment, an inner fabric may be a knit, woven ornon-woven fabric, and may be treated to enhance moisture wickingproperties or to impart hydrophobic or oleophobic properties.

In some embodiments, the fabric layers may be treated with suitablematerials so as to impart properties such as flame resistance, antistatic properties, ultra violet radiation resistance, controlled infrared (I. R.) reflectance, camouflage, and the like.

In one embodiment, a laminate may include one or more additionalmembrane layers. A suitable membrane may include a hydrophilic membranelayer, an oleophobic membrane layer, or a microporous membrane layer.FIG. 4 shows a laminate in accordance with one embodiment of theinvention. A catalytically active membrane 42 is sandwiched between anouter fabric layer 44 and an inner fabric layer 46. An additional layer43 is present between the catalytically active membrane and the innerfabric layer. The additional layer 43 may be a hydrophilic membrane, anoleophobic membrane, or a microporous membrane. In an alternateembodiment, two additional layers 51 and 53 may be present between thecatalytically active membrane 52 and the inner 56 and outer 54 fabriclayers as shown in FIG. 5.

In one embodiment, the article may be a chembio agent protectiveapparel. In one embodiment, the membrane may be supported on one or morefabric layers to form the chem bio agent protective apparel, asdescribed hereinabove. In one embodiment, the chembio agent protectiveapparel may be capable of transmitting moisture vapor, may be airpermeable, and may reduce the exposure of a person to harmful chembioagents. In one embodiment, the chembio agent protective apparel mayreduce the exposure of a person to harmful chembio agents by reducingthe biological activity of the chembio agent or increasing an amount oftime for a significant amount of unreacted biologically active chembioagent to pass through the chembio agent protective apparel.

In one embodiment, a chembio agent protective apparel may includegarments such as outerwear. Outerwear may include one or more ofjackets, tops, shirts, pants, hoods, gloves, coveralls, and the like. Inone embodiment, a chembio agent protective apparel may include footwearincluding, socks, shoes, boots, and the like. In one embodiment, achembio agent may include innerwear capable of being worn in fluidcommunication with skin. In one embodiment, a chembio agent protectiveapparel may include a decontamination suit. In one embodiment, anarticle as described hereinabove may be employed in protectiveenclosures such as tents, sleeping bags, casualty bags, shelters and thelike.

In one embodiment, the article may be a filter. The term “filter,” asused herein, refers to an article that blocks, traps, or modifiescontaminants in a fluid stream passing through the article. In oneembodiment, the article may be an air filter and the nanoparticledispersed in the pores of the membrane may be capable of reacting withan air pollutant when the air filter is exposed to a gas stream. In oneembodiment, the filter may remove contaminates, such as dust, from thefilter stream as well as remove undesirable pollutants by means ofcatalytically active nanoparticles.

In some embodiments, a filter may include one or more additional layers.In one embodiment, a filter 60 may include a microporous layer 64 andthe catalytically active membrane 62 may be supported on the microporouslayer as shown in FIG. 6. In FIG. 6, 69 represents the direction offluid flow. As used herein, the term “microporous layer” may refer to alayer having a thickness of at least 1 micrometer and having pores withaverage pore size in arrange of from about 0.05 micrometers to about 10micrometers.

The protective microporous layer may separate dust particles and othercontaminants from the fluid stream. In one embodiment, the microporouslayer may be adjacent to the upstream side of the filter, and themicroporous layer may prevent dust particles from becoming embeddedwithin the active portion of the filter (for example, membrane withcatalytically active nanoparticles). In one embodiment, the microporouslayer may not only protect the catalytically active nanoparticles fromcontamination by dust particles, but may also remove dust particles fromthe fluid stream exiting the filter.

In one embodiment, a protective microporous layer may include anexpanded microporous PTFE membrane. In embodiments in which amicroporous expanded PTFE membrane is used on the upstream side of thefilter, filter cleaning methods such as shaker, reverse air, andback-pulse, may become especially effective for cleaning the filterbecause the dust will readily separate from the membrane surface due toits low surface energy. The enhanced cleanability may allow for enhancedfilter life.

In some embodiments, depending on the end-use properties desired, afilter may include more than one microporous layer or additionalmembrane layers (with or without a catalytically active nanoparticle) toprovide additional levels of filtration. By varying the number oflayers, the location of the layers (e.g., upstream or downstream of theporous membrane) and the compositions of the layers, the filters may bemade with varying properties, depending on the requirements of thedesired application for the filter. In one embodiment, one or moreadditional layers in the filter may include a chemical sorbing material,for example, activated carbon.

In some embodiments, a backup or support layer may be laminated into thefilter assembly. As is shown in FIG. 7, a filter 70 may have a catalyticactive membrane 72, a microporous membrane 74, and a sorptive layer 76.In FIG. 7, 79 represents the direction of fluid flow. The sorptive layer76 may be mounted either upstream or downstream of the microporousmembrane 74 or the catalytically active membrane 72. The sorptive layer76 may serve to absorb or adsorb other poisons and pollutants in thefluid stream. This layer may be formed from a suitable sorptivematerial, including carbon filled felt or weaves.

In some embodiments, the filter may be combined with other catalyticallyactive membranes to achieve additional features. For example, a secondcatalytically active membrane may be inserted anywhere upstream of thefirst catalytically active membrane, as is shown in FIG. 8. The filterunit 80 of FIG. 8 employs a first catalytically active membrane 81 and asecond catalytic membrane 82. In one embodiment, a layer of material 83may be included between the two layers 81, 82 to isolate the layers fromeach other and/or to provide some other function (for example, scrim,absorption, liquid separation, further catalytic function, etc.). Aprotective microporous membrane 84 and sorptive layer 86 may be providedupstream. In FIG. 8, 89 represents the direction of fluid flow. In someembodiments, the two catalytically active layers 81,82 may use identicalor similar catalytic materials. In alternate embodiments, the twocatalytically active layers 81,82 may use dissimilar catalyticmaterials. For example, one catalytically active layer may catalyticallyreduce NO_(x), the other may catalytically oxidize CO to CO₂. Inaddition, a second or a third layer may adsorb SO₃.

FIG. 9 illustrates an embodiment where multiple layers of microporousmembranes are combined in the filter. In this embodiment, the filter 90includes a first microporous membrane 94, a sorptive layer 96, acatalytic active membrane 92, a sorptive layer 93, and a secondmicroporous membrane 91. In FIG. 9, 99 represents the direction of fluidflow The sorptive layer 93 may include a material that can absorb oradsorb undesirable materials from the fluid stream before it exits thefilter, such as a carbon-filled polymer. In one embodiment, a secondmicroporous membrane 91 may resistance to distortion of the filter whenit is place in a strong fluid stream or in direct contact with filtersupport materials such as filter cages. A second microporous membrane 91may be constructed from a strong, porous, and abrasion-resistantmaterial, such as a polymer felt or mesh.

In one embodiment, the filler may in the form of a sheet, a rolled sheetor a panel. In one embodiment, the filter may be in the form of a vacuumbag, industrial baghouse, a pleated cartridge, or a flat filter panel.

In one embodiment, a method is provided to form a porous membrane havinguniformly dispersed nanoparticles by employing sol-gel techniques. Inone embodiment, a method may include impregnating a membrane with ananoparticle precursor. In some embodiments, a pre-formed commerciallyavailable membrane, such as an ePTFE membrane may be impregnated with ananoparticle precursor.

In one embodiment, a method may include providing a mixture of ananoparticle precursor and a solvent in a predetermined amount. Ananoparticle precursor-solvent mixture may be in the form of a solution,a suspension, or an emulsion. In embodiments involving application of areducing agent, a mixture of the nanoparticle precursor/solvent mayinclude a reducing agent in a desired amount. In one embodiment, ananoparticle precursor may be applied directly to the porous membraneand may be free of a solvent.

A suitable solvent may be aqueous or non-aqueous depending on thesolubility of the nanoparticle precursor in the particular solvent.Suitable solvents may include aliphatic hydrocarbons, aromatichydrocarbons, compounds with hydrogen bond accepting ability, orsolvents miscible with water. Suitable aliphatic and aromatichydrocarbon compounds may include one or more of hexane, cyclohexane,and benzene, which may be substituted with one or more alkyl groupscontaining from 1-4 carbon atoms. Suitable compounds with hydrogen-bondaccepting ability may include one or more of the following functionalgroups: hydroxyl groups, amino groups, ether groups, carbonyl groups,carboxylic ester groups, carboxylic amide groups, ureido groups,sulfoxide groups, sulfonyl groups, thioether groups, and nitrile groups.Suitable solvents may include one or more alcohols, amines, ethers,ketones, aldehydes, esters, amides, ureas, urethanes, sulfoxides,sulfones, sulfonamides, sulfate esters, thioethers, phosphines,phosphite esters, or phosphate esters. Some other examples of suitablenon-aqueous solvents include toluene, hexane, acetone, methyl ethylketone, acetophenone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone,isopropanol, ethylene glycol, propylene glycol, diethylene glycol,benzyl alcohol, furfuryl alcohol, glycerol, cyclohexanol, pyridine,piperidine, morpholine, triethanolamine, triisopropanolamine,dibutylether, 2-methoxyethyl ether, 1,2-diethoxyethane, tetrahydrofuran,p-dioxane, anisole, ethyl acetate, ethylene glycol diacetate, butylacetate, gamma-butyrolactone, ethyl benzoate, N-methylpyrrolidinone,N,N-dimethylacetamide, 1,1,3,3-tetramethylurea, thiophene,tetrahydrothiophene, dimethylsulfoxide, dimethylsulfone,methanesulfonamide, diethyl sulfate, triethylphosphite,triethylphosphate, 2,2′-thiodiethanol, acetonitrile, or benzonitrile.

A nanoparticle precursor/solvent mixture may be applied to the porousmembrane by coating, dipping, brushing, painting, or spraying such thatthe nanoparticle precursor and solvent (if employed) are able topenetrate the interstices, pores, and the interior volume of the porousmembrane. A coating technique may include forwarding roll coating,reverse roll coating, gravure coating, doctor coating, or kiss coating.In one embodiment, the solvent or the excess solution may be removedfrom the membrane pores or the surface of the membrane by vacuum drying,oven drying, and the like. Additional precursor application steps, andsubsequent drying, may be employed depending on the precursorconcentration and thickness of the membrane.

In one embodiment, a method may include exposing the membrane and thenanoparticle precursor to a stimulus to form a metal nanoparticle. Asdescribed hereinabove, a stimulus may include exposure to one or more ofexposure to thermal energy, electromagnetic radiation, or water. In oneembodiment, a stimulus may include application of thermal energy and themembrane may be heated to a temperature in a range of from about 40degrees Celsius to about 120 degrees Celsius to form the nanoparticle.

In one embodiment, a method may include hydrolyzing the nanoparticleprecursor to form a metal nanoparticle. In one embodiment, thenanoparticle precursor may be hydrolyzed using the moisture in the air.In one embodiment, a nanoparticle precursor in the membrane may behydrolyzed by allowing the precursor in the membrane to react with themoisture in the air for a certain period of time.

In one embodiment, the nanoparticle precursor may be exposed to thestimulus for a time period that is less than about 1 hour. In oneembodiment, the nanoparticle precursor may be exposed to the stimulusfor a time period in a range of from about 1 hour to about 2 hours, fromabout 2 hours to about 5 hours, from about 5 hours to about 10 hours,from about 10 hours to about 20 hours, or from about 20 hours to about24 hours. In one embodiment, the nanoparticle precursor may be exposedto the stimulus for a time period that is greater than about 1 day.

In one embodiment, a method may include dispersing catalytically activenanoparticles throughout the pores of the membrane. Nanoparticles may bedispersed throughout the pores by in-situ generation of thecatalytically active particles inside the pores of the membrane. In oneembodiment, a method may include dispersing the catalytically activenanoparticles inside the pores of the membranes by sol-gel synthesisusing a nanoparticle precursor.

In one embodiment, a method may include fabrication of a laminate thatmay be used in a chembio agent protective apparel or in an air-filter.In one embodiment a catalytically active membrane may be laminated toone or more layer of a membrane, a film, or an apparel fabric. In oneembodiment, lamination may be achieved by thermal bonding, hot rolllamination, ultrasonic lamination, adhesive lamination, forced hot airlamination, or by mechanical attachment such as stitches.

In one embodiment, a laminate may be fabricated using a seamingtechnique. A seaming technique may involve stitching or heat sealing theedges to be joined and then heat sealing the seam to the inside of thelaminate. In one embodiment, the laminate may be fabricated usingadhesives or stitching. Stitching if employed may be present throughoutthe layers such as in quilting, or point bonded non-woven materials, ormay only be present at the seams or at the cuffs, for example ingarments, gloves and other articles of clothing.

In one embodiment, a method for reducing exposure of a person tobiologically active chembio agents is provided. The method may includeexposing a chembio agent to a membrane having pores and a plurality ofcatalytically active nanoparticles dispersed throughout the pores. Themethod may include infiltrating the chembio agent into the pores andreacting the chembio agent with the nanoparticles within the pores. Inone embodiment, a method may include photo catalytically reacting thechembio agent with the catalytically active nanoparticles by exposure toradiation having a wavelength of 400 nanometers or less

In one embodiment, the method may include one or both of reducing thebiological activity of the chembio agent or increasing an amount of timefor a significant amount of unreacted biologically active chembio agentto pass through the article. In one embodiment, a method may includereducing the biological activity of the chembio agent by at least 80percent. In one embodiment, a method may include increasing an amount oftime for a significant amount of unreacted biologically active chembioagent to pass through the article by at least an hour.

In one embodiment, a method may include interposing between a person anda chembio agent, a chembio agent protective apparel including a membranethat has preferential permeability towards water vapor relative to thechembio agent.

In one embodiment, a method for removing one or more contaminant(s) fromfluids is provided. A method may include exposing a fluid stream havinga contaminant to a membrane having pores and a plurality ofcatalytically active nanoparticles dispersed throughout the pores. Amethod may include infiltrating the fluid stream into the pores andreacting the contaminant with the nanoparticles within the pores. In oneembodiment, a method may include reacting or interacting a contaminantin a fluid stream with the catalytically active nanoparticle to form areaction product having properties different from that of thecontaminant in the fluid stream. In one embodiment, a method may includephoto catalytically reacting the contaminants with the catalyticallyactive nanoparticles by exposure to radiation having a wavelength of 400nanometers or less.

EXAMPLES

The following examples are intended only to illustrate methods andembodiments in accordance with the invention, and as such should not beconstrued as imposing limitations upon the clauses.

Test Methods

Moisture Vapor Transmission Rate (MVTR) is measured using the ASTM E99method unless otherwise indicated. Air permeability is measured usingthe ASTM 737 method unless otherwise indicated. Chembio agentpermeability is measured by US Army Test operating Protocol (TOP 8-2-501method) or by the ASTM F739 method unless otherwise indicated. Unitaverage weight of the membrane is determined by the ASTM D3776 methodunless otherwise indicated. EXAMPLE 1 Fabrication of catalyticallyactive e-PTFE membrane

An e-PTFE membrane (Obtained from GE Energy, Kansas City) with mean poresize of around 0.5 micrometers is dipped in a bath containing neattitanium tetraisopropoxide. The titanium isopropoxide is allowed toreact with the moisture in the air at room temperature for 24 hours.FIG. 10 shows a scanning electron microscopy micrograph of the resultingmembrane showing hydrolyzed TiO₂ nanoparticles dispersed in the porousnetwork.

Reference is made to substances, components, or ingredients in existenceat the time just before first contacted, formed in situ, blended, ormixed with one or more other substances, components, or ingredients inaccordance with the present disclosure. A substance, component oringredient identified as a reaction product, resulting mixture, or thelike may gain an identity, property, or character through a chemicalreaction or transformation during the course of contacting, in situformation, blending, or mixing operation if conducted in accordance withthis disclosure with the application of common sense and the ordinaryskill of one in the relevant art (e.g., chemist). The transformation ofchemical reactants or starting materials to chemical products or finalmaterials is a continually evolving process, independent of the speed atwhich it occurs. Accordingly, as such a transformative process is inprogress there may be a mix of starting and final materials, as well asintermediate species that may be, depending on their kinetic lifetime,easy or difficult to detect with current analytical techniques known tothose of ordinary skill in the art.

Reactants and components referred to by chemical name or formula in thespecification or claims hereof, whether referred to in the singular orplural, may be identified as they exist prior to coming into contactwith another substance referred to by chemical name or chemical type(e.g., another reactant or a solvent). Preliminary and/or transitionalchemical changes, transformations, or reactions, if any, that take placein the resulting mixture, solution, or reaction medium may be identifiedas intermediate species, master batches, and the like, and may haveutility distinct from the utility of the reaction product or finalmaterial. Other subsequent changes, transformations, or reactions mayresult from bringing the specified reactants and/or components togetherunder the conditions called for pursuant to this disclosure. In theseother subsequent changes, transformations, or reactions the reactants,ingredients, or the components to be brought together may identify orindicate the reaction product or final material.

The foregoing examples are illustrative of some features of theinvention. The appended claims are intended to claim the invention asbroadly as has been conceived and the examples herein presented areillustrative of selected embodiments from a manifold of all possibleembodiments. Accordingly, it is Applicants' intention that the appendedclaims not limit to the illustrated features of the invention by thechoice of examples utilized. As used in the claims, the word “comprises”and its grammatical variants logically also subtend and include phrasesof varying and differing extent such as for example, but not limitedthereto, “consisting essentially of” and “consisting of.” Wherenecessary, ranges have been supplied, and those ranges are inclusive ofall sub-ranges there between. It is to be expected that variations inthese ranges will suggest themselves to a practitioner having ordinaryskill in the art and, where not already dedicated to the public, theappended claims should cover those variations. Advances in science andtechnology may make equivalents and substitutions possible that are notnow contemplated by reason of the imprecision of language; thesevariations should be covered by the appended claims.

1. An article, comprising: a membrane having pores and that is airpermeable, wherein the membrane comprises a fluorinated polyolefin; anda precursor dispersed throughout the pores, wherein the precursorcomprises a metal alkoxide or a metal carbamate, wherein the precursoris essentially free of solvent, and the precursor is responsive to astimulus to form a catalytically active nanoparticle; wherein thearticle is a chembio agent protective apparel.
 2. The article as definedin claim 1, wherein the fluorinated polyolefin comprises one or both ofpolyvinylidene fluoride or polytetrafluoroethylene.
 3. The article asdefined in claim 1, wherein the fluorinated polyolefin comprisesexpanded polytetrafluoroethylene.
 4. The article as defined in claim 1,wherein the membrane comprises one or more of polyolefin, polyamide,polyester, polysulfone, polyether, polyacrylate, polystyrene,polyurethane, polyphenylene sulfone, polyphenylene oxide, or cellulosicpolymer.
 5. The article as defined in claim 1, wherein the pores have anaverage pore diameter in a range of from about 10 nanometers to about 10micrometers.
 6. The article as defined in claim 1, wherein the stimuluscomprises exposure to heat.
 7. The article as defined in claim 1,wherein the stimulus comprises exposure to water.
 8. The article asdefined in claim 1, wherein the nanoparticle comprises titanium oxide.9. The article as defined in claim 1, wherein the nanoparticle comprisessilver.
 10. The article as defined in claim 1, wherein the nanoparticlecomprises an oxide of aluminum, silver, copper, or magnesium.
 11. Thearticle as defined in claim 1, wherein the nanoparticle comprises aplurality of particles having an average particle size in a range offrom about 5 nanometers to about 500 nanometers.
 12. The article asdefined in claim 1, wherein the nanoparticle comprises a plurality ofparticles having a shape of a sphere, a cube, a crystal, a rod, a tube,a flake, a fiber, a plate, or a whisker, or the plurality includes acombination of two or more of the foregoing shapes.
 13. The article asdefined in claim 1, wherein the nanoparticle is present in an amount ina range of from about 0.1 weight percent to about 20 weight percent ofthe combined weight of the membrane and the nanoparticle.
 14. Thearticle as defined in claim 1, wherein the nanoparticle is capable ofinactivating a chembio agent when the article is contacted to a chembioagent.
 15. The article as defined in claim 14, wherein the chembio agentis a chemical agent comprising one or both of an incapacitating agent ora lachrymatory agent.
 16. The article as defined in claim 14, whereinthe chembio agent is a chemical agent comprising a vesicant.
 17. Thearticle as defined in claim 14, wherein the chembio agent is a chemicalagent comprising one or both of a pulmonary agent or a blood agent. 18.The article as defined in claim 14, wherein the chembio agent is achemical agent comprising a nerve agent.
 19. The article as defined inclaim 18, wherein the nerve agent comprises one or more of tabun, sarin,soman, cyclosarin, or GV.
 20. The article as defined in claim 14,wherein the chembio agent is a chemical agent comprising a toxin. 21.The article as defined in claim 14, wherein the chembio agent is abiological agent comprising a pathogen.
 22. The article as defined inclaim 21, wherein the pathogen is bacteria, protozoa, fungus, spore, orparasite.
 23. The article as defined in claim 21, wherein the pathogenis virus or prion.
 24. The article as defined in claim 1, wherein themembrane has an average thickness in a range of from about 0.0005 inchesto about 0.005 inches.
 25. The article as defined in claim 1, whereinthe membrane has a unit average weight in a range of from about 0.05oz/yd² to about 3.0 oz/yd².
 26. The article as defined in claim 1,wherein the membrane has air permeability that is greater than about0.01 cfm/ft² at 0.5 inches H₂O.
 27. The article as defined in claim 1,wherein the membrane has permeability to a chembio agent that is lessthan about 20 micrograms/24 hours.
 28. The article as defined in claim1, wherein the membrane is supported on one or more fabric layer. 29.The article as defined in claim 28, wherein the fabric is knit, woven,braided, tufted, or felted.
 30. The article as defined in claim 1,wherein the apparel comprises outerwear, glove, or footwear.
 31. Thearticle as defined in claim 1, wherein the apparel comprises innerwearcapable of being worn in fluid communication with skin.
 32. The articleas defined in claim 1, wherein the apparel comprises one or more of ajacket, a pant, a glove, or a hood.
 33. The article as defined in claim1, wherein the article is a decontamination suit.
 34. An article,comprising: a membrane having pores and that is air permeable, whereinthe membrane comprises a fluorinated polyolefin; a precursor dispersedthroughout the pores, wherein the precursor comprises a metal alkoxideor a metal carbamate, wherein the precursor is essentially free ofsolvent; and a plurality of nanoparticles dispersed throughout thepores, and the nanoparticles are catalytically active; wherein thenanoparticles comprise a decomposition product of the precursor; whereinthe article is a chembio agent protective apparel.